Leo Jozef Suenens (/ˈsuːnɛns/ SOO-nens) (16 July 1904 – 6 May 1996) was a Belgian Catholic prelate who served as Archbishop of Mechelen-Brussels from 1961 to 1979.

Ordained to the priesthood on 4 September 1927 by Cardinal Jozef-Ernest van Roey, Suenens initially served as a professor at Saint Mary's Institute and then taught moral philosophy and pedagogy at the Minor Seminary of Mechelen from 1930 to 1940.

He worked as a chaplain to the 9th artillery regiment of the Belgian Army in Southern France for three months, and in August 1940 he became vice-rector of the famed Catholic University of Louvain.

When Pope John XXIII called the world's bishops to Rome for the Second Vatican Council (1962–1965), he found in Suenens a man who shared his views on the need for renewal in the Church.

When the first session fell into organizational chaos under the weight of its documents, it was Suenens who, at the invitation of the Pope, rescued it from deadlock and essentially set the agenda for the entire Council.

Paul VI made him one of the four moderators of the council, along with Cardinals Gregorio Pietro Agagianian, Julius Döpfner, and Giacomo Lercaro.

"[11] In May 1969, an interview he gave to the French Catholic magazine Informations Catholiques Internationales in which he offered a critique of the Roman Curia.

[15] Suenens once remarked, "If you don't believe in the Holy Spirit or Resurrection or life after death, you should leave the Church.